Correct Answer: A
Explanation:
During interphase, which would include phases G1 to S to G2, the cell replicates its chromosomes. Specifically, it prepares for this in G1, it follows through with the replication in S, and it prepares for mitosis in G2. Choices (B) through (E) are the phases of mitosis. By this time, the chromosomes must have already been replicated.